Heating pad



FL B.VVCM F HEAT I NG PAD April 13, 1965 2 Sheets-Sheet 1 Filed Jan. 8, 1962 H. B. WOLF HEATING PAD April 13, 1965 2 Sheets-Sheet 2 Filed Jan. 8, 1962 ATTORNEYS United States Patent (3 3,173,561 HEATING PAD Herman E. Wolf, 1917 Beverly Drive, Chariotte, NJC. Filed Jan. 8, 1962, Ser. No. 164,682 4 Claims. (Cl. Mi -52.8)

This invention relates to heating devices and more particularly to electrical heating pads, underlays and the like.

The instant invention is directed more particularly to an electrical heating pad of the type adapted to be used under rugs, carpets, chairs and the like res-ting on a floor or similar surface. It is quite well recognized that areas of a room in a building will have portions thereof which are inadequately heated to serve the desires of different people in colder weather. Ordinary heating systems presently in use are inadequate to effectively and efficiently heat all areas of a room to the desired temperature to serve the individual reactions of a number of different people since some people prefer rooms of a warmer temperature while others are more comfortable with a cooler temperature. The need for a supplemental heating device of the instant type is particularly acute in offices and similar type rooms wherein some .people suffer from poor circulation in their feet and legs due in part to the sedimentary habits which are usually acquired by office employees and other employees wherein an excessive amount of sitting or the like is required. This condition is increasingly prevalent in employees of increasing age with a result that the feet and lower legs of such people are frequently cold in rooms that are otherwise adequately heated to accepted temperature standards.

Electrical heating pads of a variety of types have been developed in an attempt to provide the necessary area heating to overcome the aforementioned conditions. However, most of these prior pads have been relatively expensive to manufacture and, hence, to purchase and are of such a construction that they do not provide a uniformly heated upper surface. Also, the heat gradient between the heating element and the surface of the pad was not held to a suificiently low value in these prior pads with the result that hot spots appear in the pad and a large amount of heat is lost to the floor upon which the pad is resting. Further, these pads were constructed with a hard tough, inflexible upper surface to prevent damage to the heating element by sharp objects or the like which gave an undesirable effect or feel to a rug or carpet placed thereon.

It is therefore an object of the present invention to provide an improved electrical heating pad of novel construction which provides spot heating in a room and wherein the upper surface thereof is soft and resilient and is heated to a substantial uniform temperature with a minimum amount of heat loss to the floor upon which the pad is resting.

Another object of the present invention is to provide a heating pad of the character described which is particularly resistant to damage due to the penetration of sharp objects and to damaging blows by heavy falling objects.

A more specific object of the present invention is to provide an electrical heating pad of the character described having a heat insulating outer ply adapted to rest upon the floor upon which the pad is to be used, a second outer ply of heat conducting material, an inner ply of heat conducting sheet material positioned between said outer plies and in intimate relationship with said second outer ply to evenly conduct heat to the entire surface of said second outer ply, a resistance wire having a plurality of spaced runs positioned in intimate relationship with said heat insulating outer ply between said heat insulating out-er ply and said inner ply, and a plurality 3,1735% patented Apr. 13, 1965- of metallic strips positioned between said resistance wire and said inner ply, said metallic strips being parallel to and in superposed relation to the runs of said resistance wire to protect the wire from damage and to conduct heat therefrom to the inner ply.

Some of the objects of the invention having been stated, other objects will appear as the description proceeds, when taken in connection with the accompanying drawings, in which FIGURE 1 is a plan view of a heating pad constructed in accordance with the instant invention with portions broken away for clarity in viewing the elements positioned therebeneath;

FIGURE 2 is a fragmentary sectional view taken substantially along line 22 of FIGURE 1;

FIGURE 3 is an exploded isometric view showing a number of the elements which make up the pad shown in FIGURE 1, a jig to be used in assembling these elements and the steps in the preferred method of assembling the same; and

FIGURE 4 is an exploded isometric view similar to FIGURE 3 showing the remaining elements which make up the pad shown in FIGURE 3 and the steps in the preferred method of assembling the same.

Referring now to the drawings and more particularly to FIGURE 1, there is shown a heating pad indicated generally by the number Ill. Pad 10 generally comprises a first outer layer or ply 11, which comprises the base ply, since it is the one which is adapted to be in intimate relation with the floor upon which the pad is adapted to be placed. Ply 11 is formed from heat insulating material such as Arnherlite which has been compressed into sheet form. However, it is contemplated that any other suitable heat insulating material may be used without departing from the spirit of the present invention.

Pad 10 further comprises a second outer layer or ply 12 which is preferably constructed of a heat conductive material such as burlap. Fly 12 forms the outer surface of pad 10 opposite from ply 11. A sheet of asphalt impregnated felt material preferably forms a third or inner layer or ply 13 which is positioned between the outer layers or plies ll, 12 in intimate relation with the outer ply l2. Plies 11, 12 and 13 are preferably secured together into the composite pad 10 by a suitable latex adhesive which is of a heat conductive nature. It is contemplated, however, that any suitable adhesive which has heat conductive qualities may be used to secure the plies together.

A suitably insulated resistance wire 14 is positioned between plies 11 and 13 and has a plurality of spaced runs which are formed in a manner to be presently de scribed. Resistance wire 14 is preferably secured to ply 11 by the latex adhesive such that the same is held with the aforementioned runs in spaced relation. Also, the Amberlite material of which ply 11 is preferably constructed has the characteristic of being readily defonnable under pressure. Therefore, the runs of resistance wire 14 form small channels in the upper surface of ply 11 e P 11 i P e s d t e on. n an to b p nt y described, which aid in maintaining the runs in spaced relation. A plurality of metallic strips 15 are positioned between resistance wire 14 and ply 13 parallel to and in superposed relation to the runs of the resistance wire 14. It is noted that the metallic strips 15 are formed in such a configuration to completely cover all portions of wire 14 andare secured to both plies 11 and 13 by the aforementioned latex adhesive.

A suitable electrical connection generally indicated at 2th is provided for connection of the resistance wire 14 to a suitable electrical source (not shown). Connection 20 generally comprises a male plug 22 adapted to be received by a suitable female receptacle 21 which is :connected to the aforementioned electrical source.

fMale plug 22 has a pair of lead lines 23, 24 extending outwardly therefrom and connected at their outer ends to opposite ends 14a, 14b of resistance wire 14. A thetallic plate 25 is suitably positioned between plies 12 and 13 and has a first pair of openings 25a therein. A

bracket member 26 is positioned on the opposite side or ply 13 from plate 25 and houses therein the male plug 22. Bracket 26 is suitably connected to plate 25 by a pair of rivets 27 extending throughsuitabl'e openings in the bracket and through openings 25a in plate 25. It is noted that rivets 27 also extend through ply 13 to securely fasten the plate and bracket 26, with it's enclosed male plug 22, to ply 13 and, hence, to pad 10.

It is noted that plate 25 provides a strain relief for the connection ztl and thereby prevents the separation at lead lines 123, 24 from resistance wire 14. Also, plate 25 protects male plug 22 and lead lines 23, '24 from damage by sharp objects or blows from heavy falling objects.

It is further noted that, while the aforementioned connection 20 is prefer-red, especially on pads of relatively small dimensions, any suitable connection may be used Without departing from the spirit of the instant invention. For example, a suitable cord could be extended into the pad and suitably connected by a strain relief connection directly to the ends 14a, 14b of resistance wire 14 A binding 30 is suitably placed around the edges of the bonded plies 11, 12 and 13 to complete the pad 11) and provide the same with a pleasing appearance to the eye. The pad 10 is then in condition for use as a heating device, which is shown in FIGURE 1 as being placed beneath a suitable carpet or rug R. If desired, however, pad 10 may be used by simply placing the same upon a suitable Surface with the upper layer 12 being exposed without any other covering being placed thereover.

Referring now to FIGURES 3 and 4 wherein the steps (of the preferred method of forming pad 10 are illustrated,

a jig is shown comprising a base 40 having a plurality of v upstanding pins 41 arranged thereon in a predetermined pattern. The pins 41 at one end of the base 40 are arranged in a straight line. The pins at the other end of base 40 are arranged in a straight line and are spaced like the pins at said one end except for the two terminal pins. These terminal pins are positioned the same dis- :tance from the end of base 411 as the pins 41 at said one end but the majority of the pins 41 at said other end of the jig are spaced inwardly therefrom to provide a space for connection 20.

In forming the pad 10, ply 12 is placed on base 40 with pins 41 penetrating therethrough. Fly 12 is prefer- :ably placed thereon in a flat unwrinkled condition and is held in this condition by the pins 41. The lower sur- :face of plate 25 is coated with latex adhesive and then plate 25 is placed on top of ply 12 and is correctly positioned thereon by the two center pins 41 at said other end of the base 40 penetrating through suitable openings 25b formed therein. The lower surface of ply 13 is coated with latex adhesive and ply 13 is then placed in superposed relation to ply 12 and plate 25 on base 40 with pins 41 penetrating therethrough. Bracket 26 is placed on top of ply 13 with the openings therein in alinement with the openings 25a in plate 25. Rivets 27 are inserted through the openings in the bracket 26, openings 25a in plate 25 and ply 13 and are then peened over on the opposite side of plate 25 from bracket 26 such that the plate 25, ply 13 and bracket 26 are rigidly secured together.

The upper surface of ply 13 is then coated with a suitable layer of the latex adhesive which renders the same in condition to receive and securely hold the metallic strips 15. Metallic strips 15 are provided in different sizes as noted above with a plurality of elongate metallic strips 15a which are of substantally the same length as the spaced runs of resistance wire 14. Metallic strips 15:: are positioned on ply 13 between the two rows of at. pins 41 with the terininalends thereof terminating closely adjacent to opposite pins in the rows. It is noted that the outer or terminal metallic strips 15a are longer than the others and have holes provided therein adjacept opposite ends thereof. In positioning the semetallic strips on ply 13-, the terminal 41 in each of the rows of pins are inserted throiigh the holes therein to hold the metallic strips in position while the Wire14 is being placed thereover. Once the elongate metallicfstr ip's 15a are en tion on ply 13, they are securely held in place by the latex adhesive previously mentioned. v I I At this time, the remaining netal lic strip's 15b are placed in position on ply 13-. It is noted that metallic strips 1512 are of a length slightly greater than the length of the portions of wire 14 which connect the spaced runs and have holes formed therein adjacent opposite ends thereof. The metallic strips 1517 are positioned on base 40 in a position to overlie the connecting portions of wire 14 and parallel to the was of pins 41 with pins penetrating through the holes formed therein. Two of the metallic strips 15b are longer than the others and have an opening or hole formed in one end portion thereof. These longer metallic strips are placedfon, ply 13 ,be; tween bracket 26 and the aforementioned offset terminal ine. was the case with the metallic strips 15a, the metallic strips 15b are securely held in position by the latex adhesive previously applied to the upper surface of ply 13.

Metallic strips 15 are coated with a layer of the lateii adhesive to serve as a bond for the runs of resistance wire 14-. Resistance: Wire 1413 then placed on taper ply 13 and metallic strips 15 by connecting end portion tea to lead linezs extending outwardly from male lug 22 and by pa sing the resistance wire outwardly ftofii the bracket 26 in superposed relation to one of the longer metallic strips 15hr Resistance wire 14 is then p ssed around the oft-set terminal pin on that side of base 41) and is carried outwardly therefrom and passed around the terminal pin and the pin adjacent thereto at said one end of the jig in superposed relation to one of the metallic strips 155. The thusly formed run extends longitudinally of the jig in superposed relation to the teiininal metallic strip 15a on that side at one 41 The resistance wire is then carried superposed relation to another one of the metallic s'tr-ips 15a to said other end of the jig and passed around two of the inwardly spaced pins 41. This procedure is continued until the resistance wire is passed around all of pins 41 on base 40. The resistance wire 14 is then carried in superposed relation to the other longer metallic strip 15b to a ositio'n where the end portion 14b is connected to lead line 24 extending outwardly from male plug 22.

Ply 11 is placed over sistance wire 14 and relation therewith to 14 to form the ply 13, metallic strips 15 and re pressed downwardly into intimate cause the runs of resistance wire aforementioned channels which aid in na ntaining the runs in spaced relation. The latex adnesive on ply 13 and metallic strips 15 bonds ply 11 thereto and the resultant bonded plies, metallic strips and resistance wire are removed from base 40 and pins 41 and inverted. The binding 30 is then placed around the outer edges thereof to complete the pad 10.

The above recited method of assembling pad 10 is preferred since it allows a visual review of the relative position of each element as the same is assembled. Also, the above recited method allows the ply 11 to be pr ss into intimate relation With resistance wire 14 S that the runs of the wire form the aforementioned channels. The visual review and channels are highly desirable in a pad of the instant type. It is contemplated within the scope of the present invention that other more difficult methods could poss bly be used to :a semble a pad of the instant type which is devoid of the aforementioned channels or wnerein the channels are ipresent but are formed with greater d fliculty,

In operation, pad is placed upon a suitable surface to be heated with the lower ply 11 in contact with the floor or the like and with the upper ply 12 facing upwardly. The female receptacle 21, which in turn is connected to a suitable electrical source, is connected to male plug 22 to deliver electrical energy to the resistance wire 14. The heat given oft by resistance wire 14 upon the application of electrical energy thereto is transmitted upwardly by conduction through the metallic strips 15 and ply 13 to the upper ply 12. It is noted that the conduction of heat upwardly by ply 13 serves to diffuse the heat over substantially the entire area of the pad such that a substantially even temperature is achieved over substantially the entire upper surface. The metallic strips 15 not only serve to conduct the heat from the resistance wire 14 to ply 13 but also protect the resistance wire from damage caused by the penetration of sharp objects into the pad or by blows from heavy falling objects.

It will therefore be apparent that an improved heating pad is provided of simple but rugged construction capable of withstanding extremely hard use while providing a substantially even heat over substantially the entire surface area of the pad and while decreasing the amount of heat lost to the floor or the like.

In the drawings and specification there has been set forth a preferred embodiment of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being defined in the claims.

I claim:

1. A heat radiating pad comprising opposing outer base and face plies of sheet material, an inner ply of heat conductive sheet material positioned between said outer plies and in intimate relationship with said outer face ply, a resistance wire having a plurality of spaced runs positioned between said outer base ply and said inner ply and in intimate contact with said outer base ply, and a protective metallic strip positioned in superposed, inti mate and parallel relationship to each of the runs of said wire, said strips being of substantially the same length as said runs so that said metallic strips completely cover said runs of resistance wire to protect the wire from damage by sharp or heavy objects dropped upon the pad.

2. A heat radiating pad comprising a base ply of heat insulating sheet material, a resistance wire having a plurality of spaced runs positioned in superposed intimate relation to said base ply, a plurality of protective metallic strips positioned in superposed intimate relation to the runs of said wire and being of sufiicient dimensions to substantially cover the runs of said wire to protect the wire from damage by sharp or heavy objects forced against the pad, and a face ply of heat conductive sheet material positioned in superposed relation to said metallic strips.

3. A heat radiating pad comprising a base ply of heat insulating sheet material, a resistance wire having a plu rality of spaced runs positioned in superposed, intimate relation to said base ply, a plurality of metallic strips dis posed in superposed, intimate relation to said runs of resistance Wire and being of such length and width as to substantially cover the wire to protect the same from damage by sharp and/or heavy objects dropped upon the pad, an inner ply of heat conductive sheet material positioned in superposed, intimate, covering relation to said metallic strips and said base ply, and a face ply of heat conductive sheet material disposed in superposed, intimate, covering relation to said inner ply.

4. A heat radiating pad comprising a base ply of heat insulating sheet material adapted to be placed upon a floor or the like, a resistance wire having a plurality of spaced runs positioned in superposed, intimate relation to said base ply and over substantially the entire surface of said base ply, a plurality of narrow, elongate metallic strips disposed in superposed intimate relation to the runs of wire and of such dimensions that the runs of wire are completely covered thereby, an inner ply of heat conductive sheet material disposed in superposed, intimate, covering relation to said metallic strips, a face ply of flexible, heat conductive, wear resistant sheet material disposed in superposed, intimate covering relation to said inner ply, and heat conductive adhesive means bonding said plies, metallic strips and resistance wire into a composite pad.

References Cited by the Examiner UNITED STATES PATENTS 2,052,644 9/36 Murphy 219-528 2,423,196 7/47 MacKendrick 156-173 2,592,201 4/52 Shaw 156-173 2,625,378 1/53 Nason -171 2,771,537 11/56 Lichtenstein 219-529 2,802,091 8/57 MacKendrick 219-529 2,802,346 8/57 Simmons 62-276 2,889,445 6/59 Wolf 219-345 RICHARD M. WOOD, Primary Examiner,

MAX L. LEVY, Examiner, 

1. A HEATING RADIATING PAD COMPRISING OPPOSING OUTER BASE AND FACE PLIES OF SHEET MATERIAL, AN INNER PLY OF HEAT CONDUCTIVE SHEET MATERIAL POSITIONED BETWEEN SAID OUTER PLIES AND IN INTIMATE RELATIONSHIP WITH SAID OUTER FACE PLY, A RESISTANCE WIRE HAVING A PLURALITY OF SPACED RUNS POSITIONED BETWEEN SAID OUTER BASE PLY AND SAID INNER PLY AND IN INTIMATE CONTACT WITH SAID OUTER BASE PLY, AND A PROTECTIVE METALLIC STRIP POSITIONED IN SUPERPOSED, INTIMATE AND PARALLEL RELATIONSHIP TO EACH OF THE RUNS OF SAID WIRE, SAID STRIPS BEING OF SUBSTANTIALLY THE SAME LENGTH AS SAID RUNS SO THAT SAID METALLIC STRIPS COMPLETELY COVER SAID RUNS OF RESISTANCE WIRE TO PROTECTIVE THE WIRE FROM DAMAGE BY SHARP OR HEAVY OBJECTS DROPPED UPON THE PAD. 